Question 1

How much heat is evolved upon the complete oxidation of 6 g of aluminum at 25°C and 1 atm pressure? (   for Al2O3 is -1676 kJ/mol.)
4Al(s)+ 3O2(g)→ 2Al2O3(s)

Accepted Answer

A) 9.238 × 103 kJ 
B) 342.3 kJ 
C) 684.7 kJ 
D) 171.1 kJ 
E) 85.59 kJ 
A) 9.238 × 103 kJ 
B) 342.3 kJ 
C) 684.7 kJ 
D) 171.1 kJ 
E) 85.59 kJ

Question 2

Which of the following statements is incorrect?

Accepted Answer

A) Internal energy is a state function. 
B) The value of q is positive when heat flows into a system from the surroundings. 
C) The value of q is positive in an endothermic process. 
D) Heat flows from a system into the surroundings in an endothermic process. 
E) Enthalpy is a state function. 
A) Internal energy is a state function. 
B) The value of q is positive when heat flows into a system from the surroundings. 
C) The value of q is positive in an endothermic process. 
D) Heat flows from a system into the surroundings in an endothermic process. 
E) Enthalpy is a state function.

Question 3

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid potassium bromate,KBrO3?

Accepted Answer

A) K(s)+ Br(g)+ 3O(g)→ KBrO3(s) 
B) K(g)+ Br(g)+ 3O(g)→ KBrO3(s) 
C) K(g)+   Br2(g)+   O2(g)→ KBrO3(s) 
D) K(s)+   Br2(l)+   O2(g)→ KBrO3(s) 
E) K(s)+   Br2(g)+   O2(g)→ KBrO3(s) 
A) K(s)+ Br(g)+ 3O(g)→ KBrO3(s) 
B) K(g)+ Br(g)+ 3O(g)→ KBrO3(s) 
C) K(g)+   Br2(g)+   O2(g)→ KBrO3(s) 
D) K(s)+   Br2(l)+   O2(g)→ KBrO3(s) 
E) K(s)+   Br2(g)+   O2(g)→ KBrO3(s)

Question 4

The reaction of iron with hydrochloric acid is represented by the following thermochemical equation.
Fe(s)+ 2HCl(aq)→ FeCl2(aq)+ H2(g); ΔH° = -87.9 kJ
How much heat is liberated at constant pressure if 0.154 g of iron reacts with 25.7 mL of 0.358 M HCl?

Accepted Answer

A) 1.85 kJ 
B) 13.5 kJ 
C) 0.242 kJ 
D) 0.404 kJ 
E) 87.9 kJ 
A) 1.85 kJ 
B) 13.5 kJ 
C) 0.242 kJ 
D) 0.404 kJ 
E) 87.9 kJ

Question 5

From the following information,determine the enthalpy of formation of C2H4(g).   C2H4(g)→ C(s)+ H2(g); ΔH = -26.2 kJ

Accepted Answer

A) -26.2 kJ/mol 
B) 26.2 kJ/mol 
C) 104.8 kJ/mol 
D) -52.4 kJ/mol 
E) 52.4 kJ/mol 
A) -26.2 kJ/mol 
B) 26.2 kJ/mol 
C) 104.8 kJ/mol 
D) -52.4 kJ/mol 
E) 52.4 kJ/mol

Question 6

Two metals of equal mass with different heat capacities are subjected to the same amount of heat.Which undergoes the smaller change in temperature?

Accepted Answer

A) The metal with the higher heat capacity undergoes the smaller change in temperature. 
B) Both undergo the same change in temperature. 
C) You need to know the initial temperatures of the metals. 
D) You need to know which metals you have. 
E) The metal with the lower heat capacity undergoes the smaller change in temperature. 
A) The metal with the higher heat capacity undergoes the smaller change in temperature. 
B) Both undergo the same change in temperature. 
C) You need to know the initial temperatures of the metals. 
D) You need to know which metals you have. 
E) The metal with the lower heat capacity undergoes the smaller change in temperature.

Question 7

For which of the following equations is the enthalpy change at 1 atm pressure equal to the standard enthalpy of formation of liquid formic acid,HCOOH?

Accepted Answer

A) C(g)+ 2H(g)+ 2O(g)→ HCOOH(l) 
B) C(s)+ 2H(g)+ 2O(g)→ HCOOH(l) 
C) C(s)+ H2(g)+ O2(g)→ HCOOH(l) 
D) CO(g)+ H2O(l)→ HCOOH(l) 
E) CO2(g)+ H2(g)→ HCOOH(l) 
A) C(g)+ 2H(g)+ 2O(g)→ HCOOH(l) 
B) C(s)+ 2H(g)+ 2O(g)→ HCOOH(l) 
C) C(s)+ H2(g)+ O2(g)→ HCOOH(l) 
D) CO(g)+ H2O(l)→ HCOOH(l) 
E) CO2(g)+ H2(g)→ HCOOH(l)

Question 8

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid calcium nitrate,Ca(NO3)2?

Accepted Answer

A) Ca2+(g)+ 2NO3-(g)→ Ca(NO3)2(s) 
B) Ca(s)+ N2(g)+ 3O2(g)→ Ca(NO3)2(s) 
C) Ca(g)+ 2N(g)+ 6O(g)→ Ca(NO3)2(s) 
D) Ca(s)+ N2(g)+ 2O3(g)→ Ca(NO3)2(s) 
E) Ca2+(aq)+ 2NO3-(aq)→ Ca(NO3)2(s) 
A) Ca2+(g)+ 2NO3-(g)→ Ca(NO3)2(s) 
B) Ca(s)+ N2(g)+ 3O2(g)→ Ca(NO3)2(s) 
C) Ca(g)+ 2N(g)+ 6O(g)→ Ca(NO3)2(s) 
D) Ca(s)+ N2(g)+ 2O3(g)→ Ca(NO3)2(s) 
E) Ca2+(aq)+ 2NO3-(aq)→ Ca(NO3)2(s)

Question 9

Which of the following statements is false concerning the reaction of hydrogen gas and oxygen gas given below?
H2(g)+  
O2(g)→ H2O(l); ΔH = -285.8 kJ

Accepted Answer

A) Per mole of O2,the change in enthalpy is -571.6 kJ. 
B) The value -571.6 kJ pertains to 1 mol of liquid water. 
C) If the equation is reversed,ΔH becomes +285.8 kJ. 
D) If the equation is multiplied by 2,ΔH becomes -571.6 kJ. 
E) For the reaction H2(g)+   O2(g)→ H2O(g),ΔH is not equal to -285.8 kJ. 
A) Per mole of O2,the change in enthalpy is -571.6 kJ. 
B) The value -571.6 kJ pertains to 1 mol of liquid water. 
C) If the equation is reversed,ΔH becomes +285.8 kJ. 
D) If the equation is multiplied by 2,ΔH becomes -571.6 kJ. 
E) For the reaction H2(g)+   O2(g)→ H2O(g),ΔH is not equal to -285.8 kJ.

Question 10

The balanced equation representing the standard enthalpy of formation reaction for NH3(g)is

Accepted Answer

A) N(g)+   H2(g)→ NH3(g). 
B)    N2(g)+ 3H(g)→ NH3(g). 
C) N(g)+ 3H(g)→ NH3(g). 
D)    N2(g)+   H2(g)→ NH3(g). 
E) N2(g)+ H2(g)→ NH3(g). 
A) N(g)+   H2(g)→ NH3(g). 
B)    N2(g)+ 3H(g)→ NH3(g). 
C) N(g)+ 3H(g)→ NH3(g). 
D)    N2(g)+   H2(g)→ NH3(g). 
E) N2(g)+ H2(g)→ NH3(g).

Question 11

Given the thermochemical equation
2Al(s)+  
O2(g)→ Al2O3(s); ΔH = -1676 kJ
Find ΔH for the following reaction.
2Al2O3(s)→ 4Al(s)+ 3O2(g)

Accepted Answer

A) 838 kJ 
B) 1676 kJ 
C) -1676 kJ 
D) 3352 kJ 
E) -838 kJ 
A) 838 kJ 
B) 1676 kJ 
C) -1676 kJ 
D) 3352 kJ 
E) -838 kJ

Question 12

Exactly 209.2 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C.What is the specific heat capacity of the metal?

Accepted Answer

A) 0.598 J/(g ∙ °
C)  
B) 1.67 J/(g ∙ °
C)  
C) 14.7 J/(g ∙ °
C)  
D) 50.0 J/(g ∙ °
C)  
E) none of these 
A) 0.598 J/(g ∙ °
C)  
B) 1.67 J/(g ∙ °
C)  
C) 14.7 J/(g ∙ °
C)  
D) 50.0 J/(g ∙ °
C)  
E) none of these

Question 13

What is the standard enthalpy change for the combustion of gaseous propylene,C3H6?
C3H6(g)+  
O2(g)→ 3CO2(g)+ 3H2O(l)
Substance
ΔH°f (kJ/mol)
C3H6(g)
+20)4
CO2(g)
-393.5
H2O(l)
-285.8

Accepted Answer

A) +2017.5 kJ 
B) -2058.3 kJ 
C) -658.9 kJ 
D) -2017.5 kJ 
E) +2058.3 kJ 
A) +2017.5 kJ 
B) -2058.3 kJ 
C) -658.9 kJ 
D) -2017.5 kJ 
E) +2058.3 kJ

Question 14

Given:
4AlCl3(s)+ 3O2(g)→ 2Al2O3(s)+ 6Cl2(g); ΔH = -529.0 kJ
Determine ΔH for the following thermochemical equation.
Cl2(g)+  Al2O3(s)→  AlCl3(s)+ O2(g)

Accepted Answer

A) +264.5 kJ 
B) +529.0 kJ 
C) +88.2 kJ 
D) +176.3 kJ 
E) -176.3 kJ 
A) +264.5 kJ 
B) +529.0 kJ 
C) +88.2 kJ 
D) +176.3 kJ 
E) -176.3 kJ

Question 15

At constant pressure,the sign of q for the process CO2(s)→ CO2(g)is expected to be

Accepted Answer

A) positive,and the process is exothermic. 
B) negative,and the process is exothermic. 
C) impossible to predict. 
D) positive,and the process is endothermic. 
E) negative,and the process is endothermic. 
A) positive,and the process is exothermic. 
B) negative,and the process is exothermic. 
C) impossible to predict. 
D) positive,and the process is endothermic. 
E) negative,and the process is endothermic.

Question 16

What is the kinetic energy of a 2000-lb car traveling at 59 miles per hour? (1 lb = 0.4536 kg,1 mi = 1.609 km)

Accepted Answer

A) 3.2 × 10-7 J 
B) 1.5 × 106 J 
C) 5.3 × 1019 J 
D) 3.2 × 105 J 
E) 4.7 × 10-8 J 
A) 3.2 × 10-7 J 
B) 1.5 × 106 J 
C) 5.3 × 1019 J 
D) 3.2 × 105 J 
E) 4.7 × 10-8 J

Question 17

What is ΔH° for the following reaction?
2C2H2(g)+ 5O2(g)→ 4CO2(g)+ 2H2O(l)
Substance
ΔH°f (kJ/mol)
C2H2(g)
+226.7
CO2(g)
-393.5
H2O(l)
-285.8

Accepted Answer

A) +1692.2 kJ 
B) -452.6 kJ 
C) -1692.2 kJ 
D) +2599.0 kJ 
E) -2599.0 kJ 
A) +1692.2 kJ 
B) -452.6 kJ 
C) -1692.2 kJ 
D) +2599.0 kJ 
E) -2599.0 kJ

Question 18

A 100 g sample of each of the following metals is heated from 35°C to 45°C.Which metal absorbs the lowest amount of heat energy?
Metal
Specific Heat
Copper
0)385 J/(g ∙ °C)
Magnesium
1)02 J/(g ∙ °C)
Mercury
0)138 J/(g ∙ °C)
Silver
0)237 J/(g ∙ °C)
Lead
0)129 J/(g ∙ °C)

Accepted Answer

A) lead 
B) magnesium 
C) silver 
D) mercury 
E) copper 
A) lead 
B) magnesium 
C) silver 
D) mercury 
E) copper

Question 19

How much heat is liberated at constant pressure when 97.7 g of calcium oxide reacts with 29.0 L of carbon dioxide gas,measured at 1.00 atm pressure and 25.0°C? (R = 0.0821 L • atm/(K • mol))
CaO(s)+ CO2(g)→ CaCO3(s); ΔH° = -178.3 kJ

Accepted Answer

A) -3.11 × 102 kJ 
B) -1.74 × 104 kJ 
C) -5.22 × 102 kJ 
D) -2.11 × 102 kJ 
E) -5.17 × 103 kJ 
A) -3.11 × 102 kJ 
B) -1.74 × 104 kJ 
C) -5.22 × 102 kJ 
D) -2.11 × 102 kJ 
E) -5.17 × 103 kJ

Question 20

Consider the following changes at constant temperature and pressure:
H2O(s)→ H2O(l); ΔH1
H2O(l)→ H2O(g); ΔH2
H2O(g)→ H2O(s); ΔH3
Using Hess's law,the sum ΔH1 + ΔH2 + ΔH3 is

Accepted Answer

A) equal to zero. 
B) sometimes greater than zero and sometimes less than zero. 
C) less than zero. 
D) cannot be determined without numerical values for ΔH. 
E) greater than zero. 
A) equal to zero. 
B) sometimes greater than zero and sometimes less than zero. 
C) less than zero. 
D) cannot be determined without numerical values for ΔH. 
E) greater than zero.

Exam 6: Thermochemistry

How much heat is evolved upon the complete oxidation of 6 g of aluminum at 25°C and 1 atm pressure? ( for Al2O3 is -1676 kJ/mol.) 4Al(s)+ 3O2(g)→ 2Al2O3(s)

Which of the following statements is incorrect?

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid potassium bromate,KBrO3?

The reaction of iron with hydrochloric acid is represented by the following thermochemical equation. Fe(s)+ 2HCl(aq)→ FeCl2(aq)+ H2(g); ΔH° = -87.9 kJ How much heat is liberated at constant pressure if 0.154 g of iron reacts with 25.7 mL of 0.358 M HCl?

From the following information,determine the enthalpy of formation of C2H4(g). C2H4(g)→ C(s)+ H2(g); ΔH = -26.2 kJ

Two metals of equal mass with different heat capacities are subjected to the same amount of heat.Which undergoes the smaller change in temperature?

For which of the following equations is the enthalpy change at 1 atm pressure equal to the standard enthalpy of formation of liquid formic acid,HCOOH?

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid calcium nitrate,Ca(NO3)2?

Which of the following statements is false concerning the reaction of hydrogen gas and oxygen gas given below? H2(g)+ O2(g)→ H2O(l); ΔH = -285.8 kJ

The balanced equation representing the standard enthalpy of formation reaction for NH3(g)is

Given the thermochemical equation 2Al(s)+ O2(g)→ Al2O3(s); ΔH = -1676 kJ Find ΔH for the following reaction. 2Al2O3(s)→ 4Al(s)+ 3O2(g)

Exactly 209.2 J will raise the temperature of 10.0 g of a metal from 25.0°C to 60.0°C.What is the specific heat capacity of the metal?

What is the standard enthalpy change for the combustion of gaseous propylene,C3H6? C3H6(g)+ O2(g)→ 3CO2(g)+ 3H2O(l) Substance ΔH°f (kJ/mol) C3H6(g) +20)4 CO2(g) -393.5 H2O(l) -285.8

Given: 4AlCl3(s)+ 3O2(g)→ 2Al2O3(s)+ 6Cl2(g); ΔH = -529.0 kJ Determine ΔH for the following thermochemical equation. Cl2(g)+ Al2O3(s)→ AlCl3(s)+O2(g)

At constant pressure,the sign of q for the process CO2(s)→ CO2(g)is expected to be

What is the kinetic energy of a 2000-lb car traveling at 59 miles per hour? (1 lb = 0.4536 kg,1 mi = 1.609 km)

What is ΔH° for the following reaction? 2C2H2(g)+ 5O2(g)→ 4CO2(g)+ 2H2O(l) Substance ΔH°f (kJ/mol) C2H2(g) +226.7 CO2(g) -393.5 H2O(l) -285.8

A 100 g sample of each of the following metals is heated from 35°C to 45°C.Which metal absorbs the lowest amount of heat energy? Metal Specific Heat Copper 0)385 J/(g ∙ °C) Magnesium 1)02 J/(g ∙ °C) Mercury 0)138 J/(g ∙ °C) Silver 0)237 J/(g ∙ °C) Lead 0)129 J/(g ∙ °C)

How much heat is liberated at constant pressure when 97.7 g of calcium oxide reacts with 29.0 L of carbon dioxide gas,measured at 1.00 atm pressure and 25.0°C? (R = 0.0821 L • atm/(K • mol)) CaO(s)+ CO2(g)→ CaCO3(s); ΔH° = -178.3 kJ

Consider the following changes at constant temperature and pressure: H2O(s)→ H2O(l); ΔH1 H2O(l)→ H2O(g); ΔH2 H2O(g)→ H2O(s); ΔH3 Using Hess's law,the sum ΔH1 + ΔH2 + ΔH3 is

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How much heat is evolved upon the complete oxidation of 6 g of aluminum at 25°C and 1 atm pressure? ( for Al₂O₃ is -1676 kJ/mol.) 4Al(s)+ 3O₂(g)→ 2Al₂O₃(s)

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid potassium bromate,KBrO₃?

The reaction of iron with hydrochloric acid is represented by the following thermochemical equation. Fe(s)+ 2HCl(aq)→ FeCl₂(aq)+ H₂(g); ΔH° = -87.9 kJ How much heat is liberated at constant pressure if 0.154 g of iron reacts with 25.7 mL of 0.358 M HCl?

From the following information,determine the enthalpy of formation of C₂H₄(g). C₂H₄(g)→ C(s)+ H₂(g); ΔH = -26.2 kJ

The enthalpy change at 1 atm of which reaction corresponds to the standard enthalpy of formation of solid calcium nitrate,Ca(NO₃)₂?

Which of the following statements is false concerning the reaction of hydrogen gas and oxygen gas given below? H₂(g)+ O₂(g)→ H₂O(l); ΔH = -285.8 kJ

The balanced equation representing the standard enthalpy of formation reaction for NH₃(g)is

Given the thermochemical equation 2Al(s)+ O₂(g)→ Al₂O₃(s); ΔH = -1676 kJ Find ΔH for the following reaction. 2Al₂O₃(s)→ 4Al(s)+ 3O₂(g)

What is the standard enthalpy change for the combustion of gaseous propylene,C₃H₆? C₃H₆(g)+ O₂(g)→ 3CO₂(g)+ 3H₂O(l) Substance ΔH°_f (kJ/mol) C₃H₆(g) +20)4 CO₂(g) -393.5 H₂O(l) -285.8

Given: 4AlCl₃(s)+ 3O₂(g)→ 2Al₂O₃(s)+ 6Cl₂(g); ΔH = -529.0 kJ Determine ΔH for the following thermochemical equation. Cl₂(g)+ Al₂O₃(s)→ AlCl₃(s)+O₂(g)

At constant pressure,the sign of q for the process CO₂(s)→ CO₂(g)is expected to be

What is ΔH° for the following reaction? 2C₂H₂(g)+ 5O₂(g)→ 4CO₂(g)+ 2H₂O(l) Substance ΔH°_f (kJ/mol) C₂H₂(g) +226.7 CO₂(g) -393.5 H₂O(l) -285.8

How much heat is liberated at constant pressure when 97.7 g of calcium oxide reacts with 29.0 L of carbon dioxide gas,measured at 1.00 atm pressure and 25.0°C? (R = 0.0821 L • atm/(K • mol)) CaO(s)+ CO₂(g)→ CaCO₃(s); ΔH° = -178.3 kJ

Consider the following changes at constant temperature and pressure: H₂O(s)→ H₂O(l); ΔH₁ H₂O(l)→ H₂O(g); ΔH₂ H₂O(g)→ H₂O(s); ΔH₃ Using Hess's law,the sum ΔH₁ + ΔH₂ + ΔH₃ is